One form of crusher which is frequently used for crushing or comminuting minerals, rock, coal, waste and other ore-like materials is a conical crusher. The conical crusher has a downwardly expanding central conical member which rotates or gyrates within an outer downwardly expanding frustroconically shaped member typically called a bowl. The central conical member generally has a wearing cover or liner typically called a mantle. The outside surface of the mantle provides a crushing surface for the rock crusher. The bowl is also provided with a wearing cover or liner, which forms the other crushing surface.
Another form of crusher which is frequently utilized for primary crushing operations is a gyratory crusher. The gyratory crusher has a downwardly expanding central conical member which rotates or gyrates within an outer upwardly expanding frustroconically shaped member typically called a shell. The shell can be comprised of two or more pieces, e.g., a top shell and a bottom shell. The central conical member generally has a wearing cover or a liner called a mantle. The mantle can be one or more pieces. The outside surface of the mantle provides a crushing surface for the rock crusher. The shell is also protected by a wearing cover or liner which provides the other crushing surface.
Conventional wearing covers or liners disposed over the shell are comprised of four-sided segments formed with a curvature appropriate to fit against the cylindrical surface of the shell. Liners formed from segments are utilized as opposed to one-piece liners. Liners formed from segments reduce susceptibility to breaking and bending caused by crushing forces and imperfect dimensional fits resulting from casting tolerances. The segments are typically called concaves and are formed of cast or fabricated steel.
The concaves are manually attached to the inside surface of the shell. A backing material, such as zinc, epoxy, or other adhesive, holds the concaves to the inside surface, fills gaps, and provides a uniform support surface. Concaves generally have a curvilinear outside and inside surface. The outside surface faces the inside surface of the shell, and the inside surface is the crushing surface that is opposite the mantle. Concaves can be arranged in rows over the inside surface of the top shell and the bottom shell of the gyratory crusher. For example, one type of gyratory crusher manufactured by Nordberg, Inc. of Milwaukee, Wis. can have five rows of concaves covering a top shell and a bottom shell.
The outside surface of each concave typically includes a recessed portion between the feet or outer bands. The recessed portion provides a gap between the outside surface of the concave and the inside surface of the top shell. Backing material is placed in the recessed portion or gap between the shell and the concave.
Installing the relatively small concaves is labor intensive and increases the cost associated with repairing and assembling rock crushers. The application of the concaves is time consuming, and improperly installed elements can be subject to loosening and falling out. In addition, the concaves must be positioned on the inside surface of the shell so that the concaves do not interfere with the operation of other elements, such as, the spider, the mantle, or other structures.
Thus, it is desirable to provide wear resistant segments or concaves in a form which are not susceptible to bending or breaking and yet can be more easily installed. Further, there is a need for concaves which are more easily aligned when installed. Further, there is a need for a concave which is less susceptible to movement in a vertical direction.